Integratable optical waveguide isolator

A method, comprising:

• polarizing a forward propagating wave received at an input port within a semiconductor die into a polarized forward propagating wave having a first plane of polarization;
• rotating the polarized forward propagating wave by an angle to a second plane of polarization with a non-reciprocal rotator disposed within the semiconductor die;
• rotating the polarized forward propagating wave from the second plane of polarization back to the first plane of polarization with a reciprocal rotator disposed within the semiconductor die;
• and
• coupling the polarized forward propagating wave having the first plane of polarization to an output port within the semiconductor die.

A system, comprising:

• an optical source coupled to generate an optical signal responsive to an electronic processing device;
• an optical fiber;
• and
• an optical isolator coupled between the optical source and the optical fiber, the optical isolator including:
• a first evanescent coupler including first and second ports, the first evanescent coupler to receive a forward propagating wave at the first port and to output a polarized forward propagating wave having a first plane of polarization at the second port;
• a non-reciprocal rotator coupled to receive the polarized forward propagating wave from the second port of the first evanescent coupler and to rotate the polarized forward propagating wave from the first plane of polarization to a second plane of polarization;
• a reciprocal rotator coupled to the non-reciprocal rotator to receive the polarized forward propagating wave and to rotate the polarized forward propagating wave from the second plane of polarization back to the first plane of polarization;
• and
• a second evanescent coupler including third and fourth ports, the third port coupled to the reciprocal rotator to receive the polarized forward propagating wave and to pass the polarized forward propagating wave having the first plane of polarization to the fourth port.